• 제목/요약/키워드: Tehran

검색결과 1,058건 처리시간 0.029초

Nonlinear finite element modeling of steel-sheathed cold-formed steel shear walls

  • Borzoo, Shahin;Ghaderi, Seyed Rasoul Mir;Mohebi, Saeed;Rahimzadeh, Ali
    • Steel and Composite Structures
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    • 제22권1호
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    • pp.79-89
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    • 2016
  • Cold formed steel shear panel is one of the main components to bearing lateral load in low and mid-rise cold formed steel structures. This paper uses finite element analysis to evaluate the stiffness, strength and failure mode at cold formed steel shear panels whit steel sheathing and nonlinear connections that are under monotonic loading. Two finite element models based on two experimental model whit different failure modes is constructed and verified. It includes analytical studies that investigate the effects of studs and steel sheathing thickness changes, fasteners spacing at panel edges, one or two sides steel sheathing and height-width ratio of wall on the lateral load capacity. Dominant failure modes include buckling of steel sheet, local buckling in boundary studs and sheet unzipping in the bottom half of the wall.

A New Approach for Thermodynamic Study on the Binding of Human Serum Albumin with Cerium Chloride

  • Rezaei Behbehani, G.;Divsalar, A.;Saboury, A.A.;Faridbod, F.;Ganjali, M.R.
    • Bulletin of the Korean Chemical Society
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    • 제30권6호
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    • pp.1262-1266
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    • 2009
  • Thermodynamics of the interaction between Cerium (III) chloride, $Ce^{3+}$, with Human Serum Albumin, HSA, was investigated at pH 7.0 and $27\;{^{\circ}C}$ in phosphate buffer by isothermal titration calorimetry. Our recently solvation model was used to reproduce the enthalpies of HSA interaction by $Ce^{3+}$. The solvation parameters recovered from our new model, attributed to the structural change of HSA and its biological activity. The interaction of HSA with $Ce^{3+}$ showed a set of two binding sites with negative cooperativity. $Ce^{3+}$ interacts with multiple sites on HSA affecting its biochemical and biophysical properties.

Thermodynamic Studies on the Interaction of Copper Ions with Carbonic Anhydrase

  • Sarraf, N.S.;Mamaghani-Rad, S.;Karbassi, F.;Saboury, A. A.
    • Bulletin of the Korean Chemical Society
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    • 제26권7호
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    • pp.1051-1056
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    • 2005
  • The interaction of bovine carbonic anhydrase II with copper ions was studied by isothermal titration microcalorimetry, circular dichroism, UV spectrophotometry and temperature scanning spectrophotometry methods at 27 ${^{\circ}C}$ in Tris buffer solution at pH = 7.5. It was indicated that there are three non-identical different binding sites on carbonic anhydrase for $Cu^{2+}$. The binding of copper ions is exothermic and can induce some minor changes in the secondary and tertiary structure of the enzyme, which does not unfold it, but can result in a decrease in both activity and stability of the enzyme.

Buckling-restrained brace with CFRP encasing: Mechanical behavior & cyclic response

  • Razavi, S. Ali;Kianmehr, Amirhossein;Hosseini, Abdollah;Mirghaderi, S. Rasoul
    • Steel and Composite Structures
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    • 제27권6호
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    • pp.675-689
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    • 2018
  • Buckling-restrained braces (BRBs) have received considerable attention in seismic design of various types of structures. Conventional BRBs are composed of steel core and surrounding steel tube filled with concrete. Eliminating the steel tube can be advantageous to BRB. In this study the idea of replacing the steel tube by CFRP layers in BRBs is proposed. The advantages of this type of BRB are mentioned, and its design criteria are introduced. The construction procedure of two BRB specimens is described. The specimens are uniaxially tested based on moderate, and severe earthquake levels and the performance of the specimens is investigated. The backbone curves resulted from the hysteresis curve are presented for the design proposes. The results of this study show that CFRP layers can effectively provide the expected performance of the encasing, and the proposed BRB can be considered a viable alternative to the conventional BRBs.

Confusing a Pollen Grain with a Parasite Egg: Infection or Traditional Medicine?

  • Mowlavi, Gholamreza;Paknezhad, Niloofar;Dupouy-Camet, Jean;Hugot, Jean Pierre
    • Parasites, Hosts and Diseases
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    • 제58권2호
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    • pp.211-212
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    • 2020
  • Camacho & Reinhard stated in the December 2019 issue of the KJP (57: 621-625) that we confused a pollen grain with an Enterobius egg found in the grave of a female adolescent residing in ancient Tehran 7,000 years ago". We want here to clarify and answer to the outlined points in their article.

Cyclic load testing and numerical modeling of concrete columns with substandard seismic details

  • Marefat, Mohammad S.;Khanmohammadi, Mohammad;Bahrani, Mohammad K.;Goli, Ali
    • Computers and Concrete
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    • 제2권5호
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    • pp.367-380
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    • 2005
  • Recent earthquakes have shown that many of existing buildings in Iran sustain heavy damage due to defective seismic details. To assess vulnerability of one common type of buildings, which consists of low rise framed concrete structures, three defective and three standard columns have been tested under reversed cyclic load. The substandard specimens suffered in average 37% loss of strength and 45% loss of energy dissipation capacity relative to standard specimens, and this was mainly due to less lateral and longitudinal reinforcement and insufficient sectional dimensions. A relationship has been developed to introduce variation of plastic length under increasing displacement amplitude. At ultimate state, the length of plastic hinge is almost equal to full depth of section. Using calibrated hysteresis models, the response of different specimens under two earthquakes has been analyzed. The analysis indicated that the ratio between displacement demand and capacity of standard specimens is about unity and that of deficient ones is about 1.7.

Type IV Monteggia-equivalent fracture in an adult: a case report

  • Yousef Fallah;Behnam Baghianimoghadam;Salar Baghbani;Amirhosein Karim
    • Clinics in Shoulder and Elbow
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    • 제26권2호
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    • pp.205-207
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    • 2023
  • A Monteggia fracture is a proximal ulnar fracture with proximal radioulnar ligamentous instability. While there is no precise definition, Monteggia-equivalent fractures are generally considered Monteggia fractures accompanied by radial head fractures. These are rare. In this study, we report a rare variation of a Bado type IV Monteggia-equivalent lesion (fracture of proximal ulnar shaft, proximal radial shaft, and radial head) and its management.